LM211QD - 115ns Differential Comparator | Texas Instruments
MPN： LM211QD ✓ 啟用中LM211QD 概覽
A differential comparator is an analog integrated circuit that compares two input voltages and changes its output state when the differential input crosses a threshold. The LM211 belongs to the broader comparator hierarchy within analog and interface ICs, where it bridges the voltage-domain gap between analog sensors or signal chains and digital control logic. Its single-channel architecture provides a clear threshold decision while its wide supply range supports both 5 V logic and dual ±15 V analog systems.
Key specifications include a maximum response time of 115 ns, maximum input bias current of 300 nA, and maximum input offset current of 70 nA. The device supports operation across -40°C to +125°C, making it suitable for industrial temperature ranges. Its open-collector and open-emitter output architecture supports wired logic and allows pull-up or pull-down networks to establish the desired output level.
The LM211 architecture includes differential inputs and strobe control for coordinating comparator decisions in larger systems. The open-collector output can sink logic-level current, while the open-emitter structure provides complementary open-ended drive. Because open outputs do not establish a passive high level by themselves, external pull-up resistors are normally required when interfacing the collector output to TTL or MOS logic.
Typical applications include pulse-width and timing circuits, zero-cross detection, sensor thresholding, overvoltage and undervoltage indication, industrial control interfaces, and relay or lamp activation. Its 115 ns response time supports decisions where propagation delay matters, while the 3.5 V to 30 V supply range permits use in both low-voltage logic systems and higher-voltage analog equipment.
When designing a circuit around the LM211QD, begin with the output pull-up network and confirm that its resistor value satisfies the required sink current, rise time, and power dissipation. Keep comparator inputs away from switching nodes and high-current return paths, and use the strobe pin only according to the manufacturer timing and logic guidance.
This page combines the LM211QD specifications, pin-compatible replacement information, application guidance, and selection criteria to support faster design decisions than a basic distributor listing. Use the Request a Quote form on this page for current commercial availability, price, and lead-time requirements.
直接替換替代品，適用於 LM211QD — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
LM211QDG4
✅ 直接替換 ⚠️ 規格未經驗證📋 參考替代品（不在目錄中）
LM211DR
✅ 直接替換 ⚠️ 規格未經驗證聯絡詢價
查看資料表 →LM211MDREP
✅ 直接替換📋 參考替代品（不在目錄中）
LM211QDRQ1
✅ 直接替換📋 參考替代品（不在目錄中）
LM211QD 最大額定值與電氣特性
| Comparator Type | Single differential comparator with strobe |
| Response Time | 115 ns |
| Supply Voltage Range | 3.5 V to 30 V |
| Number of Channels | 1 channel |
| 輸出類型 | Open-collector and open-emitter |
| Maximum Input Bias Current | 300 nA |
| Maximum Input Offset Current | 70 nA |
| Strobe Function | Yes |
| TTL Output Compatibility | Compatible |
| MOS Logic Compatibility | Compatible |
| Supported Dual Supply | ±15 V |
| Supported Logic Supply | 5 V |
| 工作溫度範圍 | -40°C to +125°C |
| 封裝 | 8-pin SOIC (D) |
| 腳位數 | 8 pins |
| 安裝類型 | Surface mount |
| Output Load Capability | Lamp and relay driving |
LM211QD 8-pin soic (d) 腳位配置指南
LM211QD（8-pin soic (d) 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： LM211QD.
請參閱 資料表 以查看完整腳位配置。
典型應用
LM211QD 適用於 6 應用s: Pulse and Timing Control, Industrial Sensor Thresholding, Overvoltage and Undervoltage Detection, Zero-Cross and Level Detection, Lamp and Relay Interface, TTL and MOS Logic Interfacing.
Pulse and Timing Control
The LM211QD is appropriate for pulse-width, edge, and timing circuits because its 115 ns response time provides a defined propagation interval for threshold transitions. It can compare a rapidly changing signal against a reference and then drive a TTL or MOS input through the open-collector output. Designers should include an appropriate pull-up resistor and account for the resistor-capacitor output rise time in addition to the specified 115 ns response time.
推薦
Industrial Sensor Thresholding
The LM211QD can convert a sensor or analog measurement into a digital decision for industrial control equipment. Its differential inputs, 300 nA maximum input bias current, and 70 nA maximum input offset current help limit errors in high-impedance sensing arrangements, while the -40°C to +125°C range supports demanding ambient conditions. The open-collector output should use a pull-up network matched to the required logic family and system noise margin.
推薦
Overvoltage and Undervoltage Detection
The LM211QD is well suited to power-supply monitoring because it can operate from 3.5 V to 30 V and switch a logic indication when a monitored voltage crosses a reference threshold. The 115 ns response permits rapid fault signaling, and the open-emitter output offers additional open-ended drive flexibility. A production design should account for input common-mode limits, output pull-up components, and fault-state behavior documented in the manufacturer datasheet.
推薦
Zero-Cross and Level Detection
The LM211QD can detect a signal crossing a reference level in zero-cross, window, or level-detection circuits. Its 115 ns response time is useful when the system must react quickly to a transition, and its differential input arrangement allows the threshold to be referenced to a local return rather than an arbitrary system ground. Protective series resistance and careful routing are important when the monitored waveform contains fast edges or high common-mode excursions.
推薦
Lamp and Relay Interface
The LM211QD can control lamps and relays by combining its comparator decision with an appropriate transistor or driver stage. The comparator provides the low-current threshold decision, while the external driver handles the load current and voltage isolation. Its open-collector output requires a pull-up arrangement, and the selected switching device must be checked for coil transients, saturation voltage, and current limits. The 3.5 V to 30 V supply range supports varied control platforms.
推薦
TTL and MOS Logic Interfacing
The LM211QD is intended for interfacing analog decisions with TTL and MOS logic systems. Its open-collector output can sink current for a low state, while an external pull-up resistor establishes the high state, and the open-emitter output adds a complementary open-ended output structure. Designers should select the pull-up value from the required rise time, sink-current capability, power consumption, and noise-immunity requirements rather than choosing it solely from the supply voltage.
推薦
推薦產品摘要
工程參考資料，適用於 LM211QD — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LM211QDG4 | LM211DR | LM211MDREP | LM211QDRQ1 | LM211D |
|---|---|---|---|---|---|---|
| Package | 8-pin SOIC (D) | 8-pin SOIC (D) | 8-pin SOIC (D) | 8-pin SOIC (D) | 8-pin SOIC (D) | 8-pin SOIC (D) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | National Semiconductor Corporation |
| Function | Single differential comparator with strobe | LM211-family differential comparator | LM211-family differential comparator | Differential comparator with strobes | LM211-family differential comparator | Compatible differential comparator |
| Response Time | 115 ns | 115 ns | 115 ns | 115 ns | 115 ns | 115 ns |
主要差異化特點
- Fast single-comparator response (對比LM211D)
- Wide single-supply operating range (對比LM211MDREP)
- Dual open-ended output structures (對比LM211QDRQ1)
設計說明
Treat the open-collector output as requiring an external pull-up resistor. Without one, the output cannot establish a valid high state on its own. Select the resistor using the required rise time, input capacitance, pull-up current, and available sink current rather than applying a universal value. Also confirm that the open-emitter output is connected to a compatible pull-down or driver arrangement before powering the circuit.
Route the differential input traces as a compact pair and keep them away from switching-node copper, relay coils, and high-current return paths. Place the input-network components close to the comparator pins to minimize parasitic pickup. When the input source is high impedance, provide a defined bias path within the device's input-current and common-mode limits, and use a ground reference that remains stable during output transitions.
The 115 ns response time does not by itself determine the usable bandwidth of the complete interface. The open-collector rise time depends on the pull-up resistance and total node capacitance, so calculate that time separately for the intended logic load. For high fan-out or long interconnects, use a lower pull-up resistance within the sink-current limit or add a suitable buffer to preserve edge quality and maintain noise margin.
合規資訊
The LM211QD is not identified as an AEC-Q100-qualified automotive part in the manufacturer product documentation. RoHS, REACH, lead-free, halogen-free, and conflict-minerals status require confirmation from the applicable manufacturer compliance documentation.
